I'm using WinSCP 5.5.2 Build 4130 trying to SSH into an OpenVMS V6.2 VAX system running Process Software SSH V2.4.A {SSH-2.0-ReflectionForSecureIT_6.1.4.0 build 3197 - Process Software SSH for OpenVMS}. Is it that OpenVMS is supported with other settings? I've been working on this for weeks and I give up.

If I use the GUI, setting timeout to 200 seconds and unchecking Optimize Connection Buffer Size, connection is made but tells me: server's host key not found in cache, gives me the key, and then asks me where to put a key to cache. Whether I say YES or NO, I get in without problems. But with the .NET client code (shown below), it dies after a minute at OPEN(SESSIONOPTIONS) saying the following message (I cut it in size because it's way too long a message). I did take the key shown in the GUI and used it with my .NET code but same issue, hangs at OPEN and then gives me same error message: